peerplays-fc/include/fc/io/iobuffer.hpp

81 lines
1.9 KiB
C++
Executable file

#pragma once
#include <fc/io/iostream.hpp>
#include <fc/exception/exception.hpp>
namespace fc
{
/**
* Records the size, but discards the data.
*/
class size_stream : public virtual fc::ostream
{
public:
size_stream( size_t s = 0):_size(s){}
size_t size()const { return _size; }
size_t seek( size_t pos ) { return _size = pos; }
virtual size_t writesome( const char* /*ignored buf*/, size_t len )
{
_size += len;
return len;
}
virtual void close(){}
virtual void flush(){}
private:
size_t _size;
};
class iobuffer : public virtual fc::iostream
{
public:
iobuffer( size_t s )
:_data(s){}
size_t size()const { return _data.size(); }
size_t pos()const { return _pos; }
size_t seek( size_t pos )
{
return _pos = std::min<size_t>(_data.size(),pos);
}
virtual size_t readsome( char* buf, size_t len )
{
auto avail = std::min<size_t>( _data.size()-_pos, len );
if( avail == 0 ) throw fc::eof_exception();
memcpy( buf, _data.data()+_pos, avail );
_pos += avail;
return avail;
}
/**
* This method may block until at least 1 character is
* available.
*/
char peek()const
{
if( _pos == _data.size() ) throw fc::eof_exception();
return _data[_pos];
}
virtual size_t writesome( const char* buf, size_t len )
{
auto avail = std::max<size_t>( _data.size(), _pos + len );
_data.resize(avail);
memcpy( _data.data()+_pos, buf, len );
_pos += avail;
return avail;
}
char* data() { return _data.data(); }
virtual void close(){}
virtual void flush(){}
private:
std::vector<char> _data;
size_t _pos;
};
}